WO 2013/045390 A1 discloses a magnetic zip fastener comprising a pair of magnetic closure elements having an outer casing. Each magnetic closure element comprises an essentially tubular inner cavity for accommodating permanent magnets with essentially circular cross-section, and magnetically inert spacer means. The permanent magnets are adapted to rotate within said cavity with respect to said casing. In a coupling position of the magnetic zip fastener the permanent magnets of one of the magnetic closure elements, by effect of attractive magnetic forces, are substantially taken into contact with the permanent magnets of the other magnetic closure element. The permanent magnets may be magnetic balls so that their magnetization directions may assume any orientation with regard to directions of main extension of the two magnetic closure elements under the influence of magnetic forces, or they may be cylinders permanently magnetized diametrically with regard to the direction of main extension and only rotating about the direction of main extension of the respective magnetic closure element. The magnetic zip fastener may replace a common zipper of a jacket.
If the two magnetic closure elements of the magnetic zip fastener known from WO 2013/045390 A1 are arranged at an offset in their directions of main extension which is more than half of the distance of the permanent magnets, attractive magnetic forces will act between the magnetic closure elements which conserve or even increase the offset and fix the magnetic closure elements at each other at this offset.
U.S. Pat. No. 4,399,595 A discloses a magnetic closure mechanism comprising two strips of flexible, non-magnetic material having permanent magnets incorporated in them. The permanent magnets are permanently magnetized diametrically with regard to the directions of main extension of the two strips. In each of the two strips the permanent magnets are alternately oriented so that neighboring faces of the permanent magnets have opposite magnetic polarity. In a closed position of the magnetic closure mechanism adjacent faces of the permanent magnets embedded in the two strips have opposite magnetic polarities and attract each other. Whereas the permanent magnets in one of the two strips are at fixed positions in the direction of main extension of the strip, the permanent magnets in the other strip are movable along the direction of main extension of the strip. Means for moving these movable permanent magnets may be used for moving them so that adjacent permanent magnets in the two strips have same polarities, thus magnetically pushing the permanent magnets of the two strips away from each other or releasing the first and second strips.
In the magnetic closure mechanism known from U.S. Pat. No. 4,399,595 A, the alignment of the two strips in their directions of main extension is ensured by a mechanical arrangement of a longitudinal extending recess of one strip into which a longitudinally extending protrusion of the other strip only completely engages if the strips are correctly aligned.
U.S. Pat. No. 2,807,841 A discloses a cabinet closure and sealing arrangement. A gasket of this arrangement includes a series of longitudinally magnetized permanent magnets providing attractive magnetic forces pulling the gasket against a metallic wall of the cabinet. The individual elongated magnets are aligned throughout the gasket with successive magnets oriented with opposite polarity so as to have pole faces of like polarity directed towards each other. This causes a repulsion of the magnetic flux which, therefore, in a closed position of a door provided with the gasket, follows a preferential path from each of the magnets to the metallic portion of the cabinet.
U.S. Pat. No. 3,633,393 A discloses a lock comprising rotary tumblers each having a magnet and provided rotatably inside a main body of the lock. The tumblers are permitted to rotate to a given position through operation of magnets incorporated in a key. The lock further comprises a locking or unlocking mechanism operating in relation to said rotary tumblers.
There still is a need of a closure device comprising two magnetic closure elements which only closes, if the two magnetic closures elements are aligned as desired, without the aid of mechanical aligning means, and a magnetic closure element suitable for making such a closure device.